Automatic traction enhancement for transaxle

Abstract

A bi-directional overrunning clutch comprising an input gear, a pair of hubs, and a roller assembly is provided. Each hub is engaged to an end of one of a pair of shaft segments of a primary drive axle. The roller assembly is disposed within the input gear and about at least a portion of each hub. The roller assembly includes spring pins, extending from the roller assembly, with ball locks adapted to engage detents on the surface of each hub, so as to form spring pin engagements between the roller assembly and the hubs. In operation, rotation of the input gear causes rotation of the roller assembly. Thereafter, rotation of the roller assembly causes rotation of the hubs via the spring pin engagements. The spring pins, however, are generally adapted to disengage the spring pin engagements when one of the hubs rotates faster than the other hub.

1. A bi-directional overrunning clutch, comprising:
 an input gear; 
 a cam gear, disposed within the input gear, having an inner cam surface; 
 a pair of hubs, each adapted to engage an end of one of a pair of shaft segments of a primary drive axle for rotation therewith; 
 a roller assembly disposed within the cam gear, the roller assembly including
 a plurality of rollers arranged in two sets of rollers, 
 a roll cage having a plurality of recesses, each roller being located within one of the recesses, the roll cage being located about at least a portion of each hub so as to position each set of rollers about at least a portion of one of the hubs, and 
 a spring pin extending from the roll cage and having a ball lock adapted to engage with a detent on a surface of one of the hubs so as to form a spring pin engagement between the roller assembly and the hub; and 
 
 wherein the inner cam surface is adapted to provide a wedging engagement with the rollers of the roller assembly when the input gear is rotated in a first direction relative to the roller assembly such that rotation of the input gear causes rotation of the roller assembly via the wedging engagement, and rotation of the roller assembly causes rotation of the hub via the spring pin engagement between the ball lock and the detent on the surface of the hub, and wherein the spring pin is adapted to disengage the spring pin engagement when the hub rotates faster than the rotation of the roller assembly. 
 
   
   
     2. The bi-directional overrunning clutch defined in  claim 1 , further comprising a plurality of spring pins extending from the roll cage, each spring pin including a ball lock adapted to engage with one of a plurality of detents along the surface of one of the hubs so as to form a plurality of spring pin engagements. 
   
   
     3. The bi-directional overrunning clutch defined in  claim 1 , further comprising a friction member disposed between the roller assembly and one of the hubs. 
   
   
     4. The bi-directional overrunning clutch defined in  claim 3 , wherein the spring pin is adapted to disengage one of the spring pin engagements when one of the hubs rotates faster relative to the other hub. 
   
   
     5. The bi-directional overrunning clutch defined in  claim 1 , wherein the roller assembly includes two loosely interlocked roll cages. 
   
   
     6. The bi-directional overrunning clutch defined in  claim 1 , wherein each hub includes a base portion and a cover portion, wherein the base portion and the cover portion are integral with each other. 
   
   
     7. A bi-directional overrunning clutch comprising:
 a gear; 
 a roller assembly, disposed within the gear, including
 a roll cage having a recess, 
 a roller located within the recess, and 
 a spring pin extending from the roll cage and having a ball lock; and 
 
 a hub, located at least partially within the roller assembly, adapted to engage an end of a shaft segment of a primary drive axle, and having a detent, on a surface of the hub, adapted to receive the ball lock of the spring pin to thereby form a spring pin engagement, and wherein the spring pin is adapted to disengage the spring pin engagement when the hub rotates faster than the rotation of the roller assembly. 
 
   
   
     8. The bi-directional overrunning clutch defined in  claim 7 , further comprising a plurality of spring pins extending from the roll cage, each spring pin including a ball lock adapted to engage with one of a plurality of detents along the surface of the hub so as to form a plurality of spring pin engagements. 
   
   
     9. The bi-directional overrunning clutch defined in  claim 7 , further comprising a friction member disposed between the roller assembly and the hub. 
   
   
     10. The bi-directional overrunning clutch defined in  claim 7 , wherein the gear has an inner cam surface and the inner cam surface is adapted to form a wedging engagement with the roller assembly. 
   
   
     11. A transaxle on a primary drive axle of a wheeled machine comprising:
 a transaxle housing; 
 an input shaft extending into the housing; 
 a transmission coupled to the input shaft through an input drive train so as to be driven by the rotary motion of the input shaft; and 
 a bi-directional overrunning clutch, disposed within the housing, coupled to the transmission through an output drive train, and comprising
 an input gear having gear teeth mated with the output drive train, 
 a roller assembly disposed within the input gear, the roller assembly including
 a plurality of rollers arranged in two sets of rollers, 
 a roll cage having a plurality of recesses, each roller being located within one of the recesses, and 
 a plurality of spring pins extending from the roll cage, 
 
 a pair of hubs, each disposed at least partially within the roller assembly, each adapted to engage an end of one of a pair of shaft segments of a primary drive axle for rotation therewith, and each having a plurality of detents along a surface of each hub; and 
 wherein each spring pin has a ball lock adapted to engage with the detents on the surfaces of the hubs so as to form a plurality of spring pin engagements between the roller assembly and the hubs, and wherein the ball lock is adapted to disengage the detent when the hub rotates faster than the rotation of the roller assembly. 
 
 
   
   
     12. The transaxle of  claim 11 , wherein the transmission is an integrated hydrostatic transmission including a hydraulic pump and a hydraulic motor. 
   
   
     13. The transaxle of  claim 11 , wherein the transmission is a clutch transmission. 
   
   
     14. The bi-directional overrunning clutch defined in  claim 11 , wherein the spring pin is adapted to disengage the ball lock from the detent when the hub rotates faster than the rotation of the roller assembly. 
   
   
     15. The transaxle of  claim 11 , wherein the transmission is a standard mechanical transmission. 
   
   
     16. A bi-directional overrunning clutch comprising:
 a gear; 
 a roller assembly, disposed within the gear, including
 a roll cage having a plurality of recesses disposed therein, and 
 a spring disposed within at least one of the plurality of recesses in the roll cage; 
 
 a hub, located at least partially within the roller assembly, adapted to engage an end of a shaft segment of a primary drive axle; and 
 an annular friction member disposed between the roller assembly and the hub, wherein the friction member is disposed coaxial with the hub and positioned such that the spring exerts a force on the friction member, thereby creating a frictional force between the friction member and the hub. 
 
   
   
     17. The bi-directional overrunning clutch of  claim 16 , further comprising:
 a second hub, located at least partially within the roller assembly, adapted to engage an end of a second shaft segment of the primary drive axle; and 
 a second friction member disposed between the roller assembly and the second hub, wherein the second friction member includes a protrusion extending into one of the plurality of recesses in the roll cage. 
 
   
   
     18. A transaxle on a primary drive axle of a wheeled machine comprising:
 a transaxle housing; 
 an input shaft extending into the housing; 
 a transmission coupled to the input shaft through an input drive train so as to be driven by the rotary motion of the input shaft; and 
 a bi-directional overrunning clutch, disposed within the housing, coupled to the transmission through an output drive train, and comprising
 an input gear having gear teeth mated with the output drive train; 
 a roller assembly, disposed within the input gear, including a roll cage having a plurality of recesses disposed therein, and a spring disposed within at least one of the plurality of recesses in the roll cage; 
 a hub, located at least partially within the roller assembly, adapted to engage an end of a shaft segment of a primary drive axle; and 
 an annular friction member disposed between the roller assembly and the hub, wherein the friction member is disposed coaxial with the hub and positioned such that the spring exerts a force on the friction member, thereby creating a frictional force between the friction member and the hub. 
 
 
   
   
     19. The transaxle of  claim 18 , wherein the transmission is an integrated hydrostatic transmission including a hydraulic pump and a hydraulic motor. 
   
   
     20. The transaxle of  claim 18 , wherein the transmission is a clutch transmission. 
   
   
     21. The transaxle of  claim 18 , wherein the transmission is a standard mechanical transmission.